Medications are administered to human patients in a wide variety of different ways. Normally, those medications which can be administered by the patient himself are in tablet or capsule form, and are taken orally and ingested into the patient's system. However, certain types of medications, such as nitroglycerin and the like, are applied topically, and are absorbed through the patient's skin for direct introduction into the patient's blood stream. Such medications are said to be introduced into the human body by "transdermal infusion" or "transdermal absorption."
Heretofore, transdermal infusion of naturally absorptive medications like nitroglycerin has been accomplished by placement of the nitrogylcerin tablet under the patient's tongue. Although this type of process could be easily administered by the average patient himself, as opposed to hypodermic injections, the release time for the medication is rather fast, such that controlled, continuous flow of medication into the patient's system is not possible. Because the placement of a tablet under the user's tongue causes a distraction to everyday activities, this type of medication procedure is typically limited to periodic requirements and/or emergency situations.
Another type of transdermal absorption medication developed is in the form of an ointment, which is applied topically, and includes a carrier, such as a petroleum base to provide a controlled release of the active ingredients. A predetermined dosage of the ointment is spread onto the patient's skin, such as the chest region, and the medication (i.e., nitroglycerin) is absorbed continuously into the systemic circulation. An applicator stick or paddle is normally used to apply the ointment to the patient, so that the medication is not inadvertently absorbed through the fingers of the person applying the medication. To insure that the medication is not accidently rubbed off of the patient's skin, a sheet of plastic film or wrap is placed over the medication area, which is held in place by adhesive tape or the like. The plastic film also prevents the amount of the dosage from being disturbed, and protects the clothing of the patient. Since the ointment must be left on the patient's skin for relatively long periods of time, usually eight or more hours per day, it is important that the medication be isolated to the extent possible, so that the patient is able to carry out his normal, daily activities. However, skin movement around the adhesive tape tends to ruin the seal about the medication, as does bathing, swimming, exercise and other similar activities. Also, additional supplies of applicators, adhesive tape, and plastic film must be kept on hand at all times.
Very recently, bandages or compresses have been developed to facilitate the application of transdermally absorbed medications. These compresses, such as the articles described hereinbelow, generally comprise a base assembly on which a medicated, gel-like disc or pad is supported. The compress is retained in a protective package for storage, and includes an adhesive arrangement to attach the medicated pad to the skin of the user, preferably at a location free of hair, such as the chest or inner arm. The compresses hold a predetermined dosage of medication, and are designed to be worn continuously (e.g., one unit per every 24 hour period), to achieve a slow, well-controlled rate of absorption into the patient's system. Heretofore, such compresses have been rather expensive, particularly for everyday use.
Presently, work is being conducted on the use of compresses to administer other types of drugs, which are not naturally transdermally absorbed, through the use of carrying agents such as D.S.M.O. The convenience of application, and slow, controlled absorption rate achieved by a compress are also beneficial in these applications.
Since such compresses are prepackaged with an exact, preselected dosage of medication, it is extremely imporant that they be capable of securely storing the liquid medication for relatively long periods of time without leaking, or effecting the purity or potency of the medication. Also, it is very advantageous that such compresses can be opened and applied easily, and will not leak once in place, even during exercise, bathing, swimming, and other similar activities. Naturally, it is further desirable that the compresses have an uncomplicated construction, which can be quickly and economically manufactured.